NULL pointer dereference in Xen
CVE-2020-29571
An issue was discovered in Xen through 4.14.x. A bounds check common to most operation time functions specific to FIFO event channels depends on the CPU observing consistent state. While the producer side uses appropriately ordered writes, the consumer side isn't protected against re-ordered reads, and may hence end up de-referencing a NULL pointer. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system. Only Arm systems may be vulnerable. Whether a system is vulnerable depends on the specific CPU. x86 systems are not vulnerable.
EPSS: 0.004 (30.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.2 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Xen
- Debian Debian_linux — versions 10.0
- Fedoraproject Fedora — versions 32, 33
- N/a — versions n/a
Weakness classification (CWE)
References
- cve@mitre.org (Patch, x_refsource_MISC, Vendor Advisory)
- cve@mitre.org (vendor-advisory, Third Party Advisory, x_refsource_DEBIAN)
- cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
- cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
- cve@mitre.org (vendor-advisory, Third Party Advisory, x_refsource_GENTOO)
Frequently asked questions
- What is CVE-2020-29571?
- CVE-2020-29571 is a medium-severity vulnerability in Xen, classified under NULL Pointer Dereference. CVSS score: 6.2/10. Published 2020-12-15.
- How severe is CVE-2020-29571?
- Medium severity. CVSS v3 base score is 6.2 out of 10.